Hazard suppression, such as fire and explosion systems, are commonly installed in buildings for protecting valuable equipment and items, such as for example found in data centers, computer rooms, laboratories, art galleries, museums, libraries, archives and the like. Conventional hazard suppression systems now commonly employ chemically inert gases such as nitrogen, argon, carbon dioxide, and mixtures thereof as the suppression agent. These gases are naturally occurring gases and, unlike formerly commonly used man-made chemicals such as Halon, do not contribute to depletion of the atmosphere's ozone layer.
To support ignition and sustain combustion, adequate levels of combustible material, oxygen and heat must be present. Conventional inert gas based suppression systems are typically designed to release sufficient inert gas into an enclosure to dilute the level of oxygen in the atmosphere within the enclosure from the normal ambient concentration of 21% by volume down to a lower concentration, depending upon the application to about as low as 12.5% in accordance with applicable standards, in order to suppress or extinguish a fire. Further, inert gas systems must be designed to release a sufficient amount of inert gas into the protected space so as to effectively suppress the fire.
In inert gas based suppression systems, the inert gas is typically stored in one or more storage vessels, such as gas cylinders. To reduce the volume of gas storage required, and therefore the number of gas cylinders required, the inert gas must be stored at a relatively high pressure, typically at a pressure of about 300 bars or more. The delivery of a large amount of high pressure inert gas into the protected space, typically a room or other enclosure, within a short period of time may cause an overpressure in the protected space. Such an overpressure could potentially damage equipment, artifacts or other items, or even the structure of the room. Consequently, it is conventional practice to provide a special vent or vents in the structure of the room or enclosure that are capable of relieving any overpressure. Such vents add cost to the suppression system and in required size are proportional to the peak mass flow rate of the high pressure inert gas into the protected space.
Such an overpressure in the protected space is generally the result of the large amount of gas being discharged into the protected space. To control the release of the high pressure inert gas from the gas storage vessel, a gas release valve is mounted to the gas discharge outlet of gas storage vessel. In its closed position, the gas release valve is operative to prevent the high pressure gas from discharging from the gas storage vessel. When activated in response to the detection of a fire or explosion within the protected space, the valve opens to allow the high pressure gas to escape from the gas storage vessel into the protected space. Characteristic of conventional gas release valves, the mass flow rate upon discharge of the high pressure gas peaks rapidly, within a few seconds following discharge and then decays exponentially.